There are a lot of color reactions shown in Corina's "Not Witchcraft" bead challenge:
http://www.gemfox.com/corinabeads/be...challenge.html Click on the "Not Witchcraft" challenge, then click on the pictures and there will be a comment on how the reaction was achieved.
Also, Jim Smircich's description of the "Black Lace" effect with intense black is available here:
http://www.smircich.com/html/black_lace.html
Have a good time! Color reactions are a lot of fun. One of my favorites is transparent dark aqua on dark ivory.
Edited to fix a link